It is well known in the art that an organosilicone gum can be used to thicken a cosmetic formulation containing organic components and organosilicone components such as dimethylcyclo-siloxanes and low molecular weight polydimethylsiloxanes. More recently, new silicone technologies have been found to thicken cosmetic formulations including silicone copolyols and their derivatives (U. S. Pat. Nos. 5,623,017 and 5,336,497), and lightly crosslinked silicone hydrosilylation addition compositions (U.S. Pat. Nos. 5,679,734 and 5,306,797). Thickening of cosmetic formulations is typically performed to minimize the product running on or from the surface to which it is applied.
It is also well known in the art that polydimethylsiloxanes, including gums and elastomeric materials, have a larger free volume than typical organic materials, thereby allowing water and other vapors to pass through them as readily as they pass through air. Consequently formulations containing silicone gums and elastomers generally do not form occlusive barriers on the skin. It is also well known in the art that polydimethylsiloxanes, including gums and elastomers, are not compatible with most organic materials used in personal care formulations, thereby making the development of homogeneous formulations with these ingredients difficult.
New information has recently been published about toxicity characteristics of octamethylcyclotetrasiloxane which is a common silicone component of many cosmetic formulations. See, SEHSC Report entitled "D4 (Octamethylcyclotetrasiloxane) Scientific Paper for Use by Member Companies" dated Jul. 20, 1998. This information would suggest that non-toxic alternatives to the use of this material would be desirable, and preferred.
The inclusion of a volatile alkylmethylsiloxane in a formulation with octamethylcyclotetrasiloxane and a polydimethylsiloxane gum has recently been described in U.S. Pat. No. 5,759,529 for the purpose of enhancing the rate of adsorption, and improving general aesthetic characteristics.
It would therefore represent a significant advance in the state of the art if a siloxane formulation could be provided which employed nontoxic silicone components in combination with a gelling agent which had improved compatibility characteristics with other cosmetic ingredient constituents, and which had substantially equivalent sensory characteristics to current siloxane cosmetic formulations.